Author(s): Sanches, Lucas Fenato ; Silva, Adriano S. ; Roman, Fernanda ; Silva, Ana P. F. ; Díaz de Tuesta, Jose Luis ; Silva, Fernando Alves ; Silva, Adrián ; Faria, Joaquim ; Gomes, Helder
Date: 2022
Persistent ID: http://hdl.handle.net/10198/27221
Origin: Biblioteca Digital do IPB
Subject(s): Magnetic carbon nanotubes; Research Subject Categories::TECHNOLOGY::Bioengineering
Plastics are among the most generated solid wastes, predominantly composed by polymers, as low-density polyethylene (LDPE), high-density polyethylene (HDPE), and polypropylene (PP).1 This work deals with the preparation of magnetic carbon nanotubes (CNTs) by catalytic chemical vapor deposition (CCVD) at 850 ºC, considering LDPE, HDPE and PP as carbon precursors representative of urban plastic solid waste in a perspective of circular economy.1 Magnetite supported in alumina nanoparticles previously synthesized by sol-gel were used as catalysts in the CCVD process. Afterward, each synthesized CNT was washed with 50% H2SO4 at 140 °C during 3 h to remove the remaining magnetite, following methods previously described.2 The successful removal of the magnetite particles was assessed measuring the ashes content of the CNTs, removals higher than 83% being achieved (ashes content of final CNT products ranging from 4.2 to 7.9%). The remaining catalyst was located inside the CNTs, conferring magnetic properties to the materials even after washing (Figure 1). BET specific surface areas of 94, 75, and 66 m2 g-1 were found for CNT_LDPE, CNT_HDPE and CNT_PP, respectively, and a slight increase of 1-5 m2 g-1 was observed after washing the materials with acid.
